Magnet core



w. EHLERS MAGNET CORE June 30, 1931.,

Filed June 26, 1926 Patented June 30, I931 UNITED STAT-ES PATENT- "OFFICE WALTHER EHLERS, OF BERLIN-'COPEITICK, GERMANY, -ASSIGNOR, BY MESNE ASSIGN- HINTS, TO GENERAL ELECTRIC COMPANY, 'A. CORPORATION OF NEW YORK mama?- coma Application filed June 26, 1926,"Se ria1 No. 118,742, and in Germany July 6, 1925.

My invention refers to magnet cores, more especially such as form part of induction coils of the Pupin system. It is an object of my invention to provide a magnet core 5 which isadapted to fulfill the varying requirements regarding its magnetic and electric properties, which are made accordin to the articular purpose for which the coi is used.

Hitherto each ma net core was made of some uniform material, either in one piece or in several pieces of equal shape, and in order to satisfy the varying. requirements mentioned above either the quality of the cores was modified or else some standard t es were used for every gmrpose without ing regard to .the most avorable quality in each case. Obviously the difiiculty in providin in go each individual case a core which fu fills all requirements becomes greater every day and renders it almost impossible to keep such cores in store.

According to the present invention now, I

build up the core from several units, but

in contradistinction to this well known step the core according to my invention is built up from units possessing difierent electric and magnetic properties, such as are required in each individual case to render the core adapted to fulfill all requirements of the case. I thus'render it possible to keep in store certain units having predetermined electric and magnetic properties, and I am therefore enabled to compose any special core that may be ordered, by merely selecting the corresponding units.

As is well known to those skilled in the art the requirements made regarding the magnetic and electric properties of the cores of Pupin coils are substantially the following: i

(a) Permeability,

(6 Stability,

2 Lowest eddy current losses, Lowest hysteresis losses.

- Assuming for instance a core to be prepared having the largest possible permea- 'bility ,L and a stability in which 'vious modifications 'will occur to (variation of u. under direct current load up to 0,1 ampere) is :less than 1 per cent, the losses by eddy currents W being smaller than 9 Q/Henry, and the losses by hysteresis In less than ohm/Henry/amp./cms.

Assuming further the following groups of units to be available for fulfilling these requirements, viz.:

(1) Hard-steel wire A =100, "=1%, W=20, h=150, (2) Solid core A 35, =+1%,W=5, h=10.

h=% (1-'150+3-10)=45. The effective permeability .=5l, which 15 obtained according to the above, cannot practically be obtained by any means hitherto known, if the limits of stability and losses are taken into consideration.

I wish it tobe understood that I do not desire tqbe limited to the exact details of construction shown and described -for oba person skilled in the art.

I claim 1. Magnet core composed of a plurality of superposed units olfering an uninterrupted path to the magnetic flux and consisting of magnetic material having a marked permeabihty, one of said units differing from another unit in its magnetic properties.

2. Magnet core composed of a plurality of superposed units offering an uninterrupted path to the magnetic flux and consisting of magnetic material having a marked permeability, one of said units differing from another unit in its magnetic and electrical properties.

3. Magnet core composed of a plurality of superposed annular units offering an uninterrupted path to the magnetic flux and consisting of magnetic material having a marked permeability, one of said units 'diflering from another unit in its magnetic properties.

4. Magnet core composed of a plurality of superposed annular units olicring an uninterrupted path to the magnetic flex and consisting of magnetic material having a marked permvability, one of said units (liffering from another unit in its magnetic and electrical properties.

In testimony whereof tnrc.

I afii'x my signa- WVALTHER EHLERS. 

